axhoaxho

The recent rumor of a 4.0L GT3RS Limited Edition reminds me of an article that I read last year.

Andreas Preuninger (Porsche motorsport manager of high-performance cars) said in an interview about the 3.8L GT3 engine:

Is there any break-through technology that overturns Mr. Preuninger's statement about the durability of a 4.0L metzger-block street car?

Thanks for any insight.

Regards,

911rox

boron steel, titanium??? and a price rise of US$25k...

doubt they can go larger reliably....

amdevo

rsr engine

axhoaxho

RSR engine is for the races, not for the street reliability usage. I forgot the exact number, yet I remember the RSR engine can only go for so many hours between rebuilds?

A 4.0L Metzger engine with street reliability and 4yrs/50K new car warranty, it can be diffferent story.

Regards,

Condor Man

50 Hours until a rebuild.

silverboy

Just curious - can't they de-tune it so it won't rev to 9K rpm but 8.2K instead...

Condor Man

Of course they could, as long it still made 500 HP.

997gt3north

- in different series this motor has a redline sub 8000rpms and very restrictive intakes
- they could easily produce a 500hp (at the crank) car with a 4.0liter engine and still put a warranty on it
- 500hp (at the wheels) with a 4.0 would require 9000rpm and putting a warranty on that would be very, very expensive

- if this is true, and it is fully NA (non hybrid), my guess is that this is a 200k+ car in the US
- at that price, the collectors will buy everyone of them and they will never see the road

cscrogham

The DP (unrestricted RSR) engines I ran were about 525hp and went to 9400rpm, lasted about 25hrs (interesting for a 24hr race, eh?). The piston pins were the limiting factor, and later enlarged a mm but still the rebuild time was less than 30hrs and cost twice as much as a standard Cup (ie-RS) engine.
I don't think that is a feasible alternative in a street car, personally I'd say the 3.8 is it with some sort of electric front hub assist.

cay187

looks similar to what bmw did building the 10 street version GTR's selling them at 250k each just so they can race that v8 engine.

mooty

interesting frontier indeed.
can't bore it.
make stroke longer (but that kills rpm range)
of course there will be warranty issues as the motor gets more stressed.
but hey, it's a 4L collector car, there are plenty of wealthy clients for couple hundred units.
i eagerly await the curtain to be drawn.

Carrera GT

Making the piston lighter, along with the con rod and crank design can increase stroke while compensating for bearing loads. While they can still bring up rpm to say 8600, engine management can avoid unwelcome problems (abrupt throttle position changes can be suppressed for example.)

Unlike the control of forced induction (note the torque plateau of the GT2 RS) the naturally aspirated car might require a "third" stage to the intake design to enable the engine to idle on pump gas in the absence of direct injection fuel metering to achieve multiple injection and ignition points with a high compression engine.

Still, I would have noted all the same limitations for a street engine at 3.8l and 450hp ... so once the impossible has been realized, I guess there's no reason to argue that 500hp is so far fetched.

Then there's the example of Sharkwerks using factory kits to build and tune 3.9's and lighter reciprocating mass producing somewhere around the 500 neddies. Strangely other vendors trying the displacement game and running even higher volumes haven't produced the same HP gains.

I'd position these model run-out specials as useful cash flow "show of strength" operations for the Porsche brand. I don't begrudge them accessing the consumer at those higher price points -- it turns into profitability and hopefully a few pennies go back into the R&D.

While the 500 horse rumored for "next" RS is appealing, it's still pretty far fetched and we can see from recent announcements that however high Porsche goes with the specs, even if this car turns out to be real, Porsche has shown no compunction in taking the prices even higher. Would I pay another $50K on top of a 997.2 RS to go from 450hp to 500hp? No. Even I am just plain not that stupid. And then track it with no warranty and no insurance? And what else can they type on the spec sheet? The carbon fenders of the GT2 RS is the only new item out there. Porsche seems to have reserved the double-bubble roof panel for the Sport Classic and that's fine. So this high HP "last" RS might cannibalize a few 450 HP sales or it might even stave off some Italia buyers from their worst mistake, if anything, it reinforces the "value" of the GT2 RS ... in simple terms, "If you're going to go big, go big!"

Riz

That is only 125 hp/liter - that is definitely possible especially for Porsche, Ferrari, BMW, MB, and even Honda. The RSR produces a lot more if unrestricted. The current RS is making over 118hp/liter already.

axhoaxho

Good to hear from someone who has first-hand experience on the RSR.

I too have my doubt about the street-reliability of boring the cylinder walls to 4.0L, as stated by Andreas Preuninger.

However, a special edition '3.8L GT3RS with Hybrid front hubs' (as seen testing in some spy pictures, and as used in the Cayenne S Hybrid) sounds like an easy enough solution for a 500hp (gasoline and electric combined) GT3RS.

We also know that Porsche is seriously racing and evangelizing the GT3 R Hybrid, and seems Hybrid is a big focus at Porsche recently. Does anyone know if the homologation rulebook also requires Porsche to run a street-version GT3 R Hybrid (aka a GT3RS with electric front hubs)?

If so, a limited edition 500hp GT3RS (3.8L engine with Hybrid front hubs) is not too far-fetched for reality.

What do you folks think?

Regards,

mattmiesnieks

The GT3 R Hybrid has a huge KERS flywheel where the passenger seat goes. Relocating that for a road car would be interesting....